The crisis of metaphysics has many roots. One of them is recognized to be a kind of semantic failure. It lies in the fact that the meaning and reference of metaphysical propositions as well as metaphysical terms seems to be problematic. This diagnosis was first established by I. Kant and then repeated by some of the XXth century philosophers. In this paper the author showed what role is played by what he called the Requirement of Reference (RR) in the analysis of the metaphysical discourse. He argues that the RR draws the limitations for the conceptual and propositional schemata of metaphysics and, at the same time, prevents metaphysics from making de re assertions and utterances. He also examined in this light some of Ludwig Wittgenstein's theses from Tractatus and Philosophical Investigations in order to argue that two sorts of metaphysical considerations are possible despite of the above-mentioned criticism. One of them is the analysis of what might be shown but cannot be expressed in language. The other is the deep analysis of the conceptual schemata that constitute the foundations of human thought.